BY B. WAGENKNECHT, ESQ. Livi 
Plate VI. shows the amount of rainfall, graphically illustrated 
for the last 25 years, z.e., from 1860 to 1884; the abscisse repre- 
senting the consecutive months, and the ordinates the respective 
amount of rainfall in each month. It will be seen on examina- 
tion of this Plate that from January to March or April, respec- 
tively—the extent of the rainy season proper—the amount of 
rainfall is invariably a maximum as compared with the remain- 
ing months, and from May to September an average minimum ; 
whereas from October to December, according to the frequency of 
thunderstorms, a mean between the both is experienced ranging 
from 1” to 10”in October, 1” to 8’ in November, and 2” tol3”in De- 
cember. Although, however, one cansee at aglance which year was 
more or less blessed with rain and at what time of it, Plate VI. 
is not suitable to demonstrate a periodicity of wet or dry years. 
For this purpose Plate VII. has been prepared, as affording a 
clearer insight; and in this the ordinates represent the amount 
of rain in each year, the baseline-divisions answering to the 
respective year in which it fell. It will be observed, on 
reference to this, that on au average every third year has a 
maximum of rainfall, the two intervening years being more or 
less dry ; and again that every third of those maximal rainfalls 
(w.e., every 9 years) a culminating point of the curve occurs, in 
which the rainfall during those 9 years arrives at a maximum, 
as in the years 1861, 1870, 1879 and probably 1888. In con- 
necting all these prominent points or maximal rainfalls by a 
line, undulating curves of similarity are obtained, which go to 
show that those intervening cycles of three years are gradually 
more deficient in rainfall the more they recede from a maxi- 
mal or culminating point of the curve, and gradually augment 
again their rainfall the nearer they approach the next point of 
culmination; so that 1861, 1870, and 1879 were blessed with 
abundant moisture, whereas 1863, 1867, 1872-73, and 1875-76, 
although not quite so abundantly blest, were also wet years ; 
furthermore, according to the 9 years’ cycle, the years 1872+9 
